While the invention is subject to a wide range of applications, it particularly relates to metal cord, such as that used to reinforce elastomers. More particularly, the present invention is directed to a metallic cord construction used to reinforce rubber articles, including pneumatic tires.
In a conventional pneumatic radial tire using metal cords, the fatigue properties of the carcass ply and belt layer are degraded, mainly by material fatigue due to repeated strain and fretting wear in the contact portion between adjacent filaments. Both of these problems are said to be alleviated by penetration of rubber into the inside of the cord. The rubber layer interposed between the steel filaments is believed to prevent rubbing between adjacent filaments, the so-called "fretting wear."
The present invention relates to a cord having improved rubber penetration into the inside of the cord. The improved rubber penetration will also provide the cord with higher corrosion resistance should the cord be exposed to moisture.
The present invention also relates to a tire having improved resistance to belt edge separation resulting from use of the 4+3 cord in the belt layers of the tire.